A catherization procedure involves the piercing of a vein or artery with a needle carrying a catheter and subsequently sliding the catheter over the needle and into the punctured blood vessel. After the needle is removed from the catheter, an intravenous tube is connected to the catheter for supplying an intravenous fluid to the patient.
Frequently, a large intravenous flow rate is required in situations where the number or sizes of the accessible veins are severely limited. Consequently, large catheters are inserted into relatively small veins, which results in tears in the veins. Catheters inserted into torn veins fall out. This naturally gives rise to a potentially dangerous circumstance.
In one method for inserting a relatively large catheter into a vein, a small catheter is deployed in a selected vein. Upon the removal of the needle used to pierce the vein, a wire is inserted through the catheter. The catheter is then removed. A vein dilating device having a substantially rigid tapered body is gradually inserted into the vein over the wire, thereby expanding the access opening in the vein. The dilator is subsequently removed and replaced with a large diameter catheter. Finally, the wire is withdrawn from the large catheter.
Obtaining access to larger organs such as the liver or the brain for purposes of viewing or operating on an inner part of the organ generally requires cutting open the respective organ. Such an invasive procedure necessarily entails trauma to the patient, extended hospital stays and excessive costs.